Nitrogen pollution interacts with heat stress to increase coral bleaching across the seascape
- 10 March 2020
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 117 (10), 5351-5357
- https://doi.org/10.1073/pnas.1915395117
Abstract
Climate change is increasing the frequency and magnitude of temperature anomalies that cause coral bleaching, leading to widespread mortality of stony corals that can fundamentally alter reef structure and function. However, bleaching often is spatially variable for a given heat stress event, and drivers of this heterogeneity are not well resolved. While small-scale experiments have shown that excess nitrogen can increase the susceptibility of a coral colony to bleaching, we lack evidence that heterogeneity in nitrogen pollution can shape spatial patterns of coral bleaching across a seascape. Using island-wide surveys of coral bleaching and nitrogen availability within a Bayesian hierarchical modeling framework, we tested the hypothesis that excess nitrogen interacts with temperature anomalies to alter coral bleaching for the two dominant genera of branching corals in Moorea, French Polynesia. For both coral genera, Pocillopora and Acropora, heat stress primarily drove bleaching prevalence (i.e., the proportion of colonies on a reef that bleached). In contrast, the severity of bleaching (i.e., the proportion of an individual colony that bleached) was positively associated with both heat stress and nitrogen availability for both genera. Importantly, nitrogen interacted with heat stress to increase bleaching severity up to twofold when nitrogen was high and heat stress was relatively low. Our finding that excess nitrogen can trigger severe bleaching even under relatively low heat stress implies that mitigating nutrient pollution may enhance the resilience of coral communities in the face of mounting stresses from global climate change.Funding Information
- National Science Foundation (OCE-1619697)
- National Science Foundation (OCE-1547952)
- National Science Foundation (OCE-1236905)
- National Science Foundation (OCE-1829393)
- National Science Foundation (OCE-1637396)
This publication has 50 references indexed in Scilit:
- Marine heatwaves threaten global biodiversity and the provision of ecosystem servicesNature Climate Change, 2019
- Systematic Revision of Symbiodiniaceae Highlights the Antiquity and Diversity of Coral EndosymbiontsCurrent Biology, 2018
- Ecosystem restructuring along the Great Barrier Reef following mass coral bleachingNature, 2018
- Spatial and temporal patterns of mass bleaching of corals in the AnthropoceneScience, 2018
- Coral reefs in the AnthropoceneNature, 2017
- The cumulative impact of annual coral bleaching can turn some coral species winners into losersGlobal Change Biology, 2014
- Coral Bleaching: Causes and MechanismsPublished by Springer Science and Business Media LLC ,2010
- Resistance and resilience of a coral reef fish community to changes in coral coverMarine Ecology Progress Series, 2008
- Coral bleaching: the winners and the losersEcology Letters, 2001
- Coral bleaching: causes and consequencesCoral Reefs, 1997